Manufacture of finishing agents for cellulosic textiles

ABSTRACT

Process for the manufacture of liquid crease-resistant finishing agents for cellulosic textile materials, the agents being based on urea and formaldehyde, from which they are obtained by condensation in two steps at specific pH values and in specific molar ratios. The agents have a long shelf life.

[22] Filed:

United States Patent [191 Petersen et a1.

[4 Nov. 18, 1975 MANUFACTURE OF FINISHING AGENTS FOR CELLULOSICTEXTIIJES [75] Inventors: Harro Petersen, Frankenthal; Klaus A Erhardt,Leimen; Wilhelm Ruemens; Heinz Bille, both of Limburgerhof, all ofGermany [73] Assignee: BASF Aktiengesellschaft,

Ludwigshafen (Rhine), Germany Sept. 26, 1973 21 Appl. No.: 400,720

[30] Foreign Application Priority Data UNITED STATES PATENTS 8/1941Conaway 8/185 3,518,042 6/1970 Pensa 8/185 3,651,139 3/1972 Feinauer8/185 3,763,106 10/1973 Markiewitz.. 8/185 3,772,292 11/1973 Martin8/185 3,801,546 4/1974 Petersen 8/185 I FOREIGN PATENTS OR APPLICATIONS1,077,344 7/1967 United Kingdom 1,204,211 9/1970 United Kingdom PrimaryExaminerBenjamin R. Padgett Assistant ExaminerD P. Walsh Attorney,Agent, or Firm-Johnston, Keil, Thompson & Shurtleff [57] ABSTRACTProcess for the manufacture of liquid crease-resistant finishing agentsfor cellulosic textile materials, the

agents being based on urea and formaldehyde, from which they areobtained by condensation in two steps at specific pH values and inspecific molar ratios. The agents have along shelf life.

10 Claims, No Drawings- ;can

MANUFACTURE OF FINISHING AGENTS FOR CELLULOSIC TEXTILES The inventionrelates to a process for the manufacof cyclic ureas and, in particular,methylol compounds of urea are employed. Monomethylolurea anddimethylolurea display the greatest reactivity amongst the currentlyknown N-methylol compounds suitable for textile finishing. They aretherefore preferred. Because of their high reactivity and their limitedsolubility, it is not possible to prepare solutions of monomethylolureaand dimethylolurea having the shelf life required in practice.Methylolureas are crosslinked to the textile substrate in the presenceof metal salt catalysts, ammonium salts or acids. If methylolureas areemployed, the stability of the liquor in the presence of such catalystsis very limited.

In-practice, it has for these reasons only been possible to employ themethylolureas in the form of powder grades, for example as spray-driedproducts. It was necessary to dissolve these solid products before use,and in the form of a solution the stability of the liquor was so limitedthat the products had to be used within 2 to 3 hours.

It isan object of the invention to provide aqueous solutions offinishing agents, based on urea and formaldehyde, whichhave a shelf lifeof at least three months, the liquor stability of which in the presenceof catalysts is substantially improved compared to the state of the art,and which, under the conditions usually employed for finishing, displaya reactivity comparable with that of methylolureas.

This object is achieved by a process for the manufacture of liquidfinishing agents for cellulosic textiles, the agents having a long shelflife, wherein the reaction mixture obtainable by reaction of urea ormethylolated urea or water-soluble urea-formaldehyde polycondensationproducts with formaldehyde in an overall molar ratio of urea:formaldehyde of 1 :3 10 in aqueous solution at pH values between and 3is adjusted to pH values between 6 and 10 and such amounts of urea areadded, at temperatures between and 80C, that an overall molar ratio ofurea to formaldehyde of 1:1.5 2.5 results.

Cellulosic textiles are woven fabrics, knitted fab- .rics and alsonon-woven fabrics of which the fibers consist of natural or regeneratedcellulose orwhich contain .such fibers mixed with other fibers.

Where methylolated urea and/or urea-formaldehyde polycondensationproducts are employed, the'overall molar ratio of urea to formaldehydeis to be understood as the molar ratio of urea to the sum of freeformaldehyde and formaldehyde already chemically bound to urea (in theform of methylol groups or of methyleneor dimethylene-ether bridges CH-OCH l The pH values are measured with a glass electrode.

For the first reaction, in acid solution, urea can be employed as, asolid or as a solution and formaldehyde be employed as a solution or inthe form of its polymers such as, for example, paraformaldehyde,trioxane or tetroxane, or in the form of its acetals, urea being reactedwith formaldehyde in the molar ratio of l:3 to 1:10, preferably in themolar ratio of 1:4 to 1:6, in the presence of a strong inorganic ororganic acid, at pH values between 3 and 0, preferably between 1.5 and2.5, to give precondensates containing urone. This condensation canadvantageously be carried out at temperatures between 60 and 100C,especially at to C.

Instead of urea it is possible to convert methylenediurea orpolymethyleneurea or their methylol compounds, such as, for example,urea-formaldehyde polycondensates, into precondensates containing uroneby means of formaldehyde. It is also possible to use, as startingmaterials for the manufacture of the precondensates containing urone,the mixtures which result from the methylolation of urea withformaldehyde and which contain, in addition to free formaldehyde, interalia the methylol compounds of urea, that is to say monomethylolurea,dimethylolurea, trimethylolurea and/or tetramethylolurea.

Suitable acid catalysts are inorganic acids, such as hydrochloric acid,sulfuric acid and phosphoric acid, and strong organic acids such aso-toluenesulfonic acid, oxalic acid and phthalic acid.

The reaction of the first stage can be carried out by treating themixture of the abovementioned starting substances and formaldehyde withan acid and then heating it to the desired condensation temperature. Itis however also possible first to heat the mixture of the startingsubstances with formaldehyde or its derivatives to the condensationtemperature and only then to add the acid. According to a preferredembodiment, formaldehyde is mixed with the acid and heated to thedesired condensation temperature. Urea or the abovementioned startingproducts are then introduced into this solution. In all embodiments itis also possible to employ mixtures of the starting components. Thereaction time depends on the temperature, amount and strength of acid,and molar ratio and concentration of the starting substances.

HOCH N Til-CH OH wherein n=1, 2 or 3, was found to take place. Theformation of the urones can be followed by means of Raman spectroscopy;they show a strong emission line in the Raman spectrum at 810 cm Theurone content can be determined quantitatively by measuring theintensity of the line.

A factor of great importance to the shelf life of the products claimedaccording to the invention is that the acid condensation of urea withformaldehyde to give products containing urone is carried out in such away that certain limiting conditions are observed. Thus, in particularwhen using molar ratios of about 1:3 to 4 in the 1st stage of thereaction, it is necessary to ensure that the neutralized samples do notbecome turbid or precipitate after standing for a short time. Suchturbidity can occurregardless of the amount of acid chosen.

On lowering the molar ratio of urea to formaldehyde, the values at whichturbidity is found shift to a higher degree of cyclization. Thus, forexample, in the condensation of urea with formaldehyde in a molar ratioof 1:4 at a temperature of 100C in the presence of 1 to 5 ml of 75percent strength sulfuric acid per kg of reaction mixture the degree ofcyclization at which turbidity is found is approx. 45 percent, whilstfor a molar ratio of 1:6 and under otherwise identical conditions thisvalue is about 55 to 60 percent.

According to the present invention, the intermediates containing uroneand free formaldehyde can be converted by further reaction with ureainto aqueous finishing agents which display high reactivity, highstability and, in contrast to the aqueous solutions of themethylolureas, excellent liquor stability. For this purpose, theprecondensates obtained in the manner described are reacted with suchamounts of urea as to give an overall molar ratio of urea toformaldehyde of 1:1.5 2.5, preferably of 1:1.7 -2.3. The urea can beadded in the form of a solid or as a solution. The reaction takes placeat a pH between 6 and 10, preferably between 6.4 and 9 and attemperatures between 20 and 80C, preferably at 30 to 60C. The reactiontime depends on the temperature and on the pH and is between one andfive hours. The reaction can be followed, for example, by continuousquantitative determination of the free formaldehyde in the solution. Thereaction is complete when the concentration of free formaldehyde showspractically no further decrease.

The liquid textile finishes thus produced show an excellent shelf life.When stored at temperatures below 25C, they remain usable for at least 6months. This was not foreseeable.

The new finishing agents are employed in conventional manner, preferablyin the form of an aqueous impregnating bath to which the catalystsgenerally required for the crosslinking reaction are added. Potentiallyacid catalysts, which are generally known, and customary, for textilefinishing purposes, are particularly suitable. Examples of catalysts ofthis type which can be used are ammonium salts of strong acids,magnesium chloride, zinc chloride and zinc nitrate. Mixtures of severalcatalysts can also be used. The concentration of finishing agentdepends, in the usual way, on the desired effect andis generally between50 and 200 g/l. The goods being treated are impregnated with theimpregnating liquor in the usual way. Preferably, a padder is used forthis purpose. The impregnated goods are freed from excess impregnatingliquid in a known manner, for example by squeezing out. It is possibleto dry the impregnated fibrous goods to a greater or lesser extent andthen heat them to a temperature of 100 to 210C, preferably 130 to 180C,in the presence of the acid or potentially acid catalysts. in general,fixing is complete after 1 to 6 minutes under these conditions. It ispossible mechanically to shape the fibrous goods during or after dryingbefore fixing, for example by compression, crimping, ironing,calendering, embossing or pleating. Cellulosic textiles are given adurable creaseresist and shrink-resist finish in this way and theembossed effects and pleats are relatively resistant to laundering.

The previously used hydroxymethyl or alkoxymethyl compounds containingnitrogen, as well as finishing agents not containing nitrogen, can beused conjointly with the new agents. It is also possible to use,conjointly, the customary water repellents, softeners, levelling agents,wetting agents, etc., such as, in particular, polymer solutions ordispersions. Examples of water repellents are paraffin wax emulsionscontaining aluminum or zirconium, preparations containing silicones, andperfluorinated aliphatic compounds. Softeners which may be mentioned areoxyethylation products of higher fatty acids, fatty alcohols or fattyacid amines, higher-molecular polyglycol ethers, higher fatty acids,fatty alcohol sulfonates, N-stearyl-N, N -ethylideneurea andstearylamidomethylpyridinium chloride. Examples of levelling agentswhich can be used are water-soluble salts of acid esters of polybasicacids with ethylene oxide adducts or propylene oxide adducts oflong-chain basic starting material which can be oxyalkylated. Examplesof wetting agents are salts of alkylnaphthalene-sulfonic acids, thealkali metal salts of sulfonated succinic acid dioctyl ester and theadducts of alkylene oxides to fatty alcohols, alkylphenols, fatty aminesand the like. Examples of finishes which can be used are celluloseethers or cellulose esters and alginates, and also solutions ordispersions of synthetic polymers and polycondensates, for example ofpolyethylene, polyamides, oxyethylated polyamides, polyvinyl ethers,polyvinyl alcohols, polyacrylic acid or its esters and amides andcorresponding polymethacrylic compounds, polyvinylpropionate,polyvinylpyrrolidone and copolymers, for example those of vinyl chlorideand acrylates, of butadiene and styrene or acrylonitrile or ofvinylidene chlorde, B-chloroalkylacrylates or vinyl ethyl ether andacrylamide or the amides of crotonic acid or maleic acid, or ofN-methylolmethacrylamide and other polymerizable compounds. Theseadditional auxiliaries are in general employed in amounts of 0.3 to 4percent, preferably l to 2.5 percent, relative to the weight of the drytextile goods; in special cases, these amounts can be exceeded.

The parts and percentages mentioned in the Examples which follow areunits by weight. The relationship of parts by weight to parts by volumeis as that of one kilogram to one liter.

EXAMPLE 1 2 parts of 50 percent strength sulfuric acid are added to 540parts of a 40 percent strength formaldehyde solution and the mixture isheated to C. 157.8 parts of a 68.5% strength urea solution areintroduced at this temperature over a period of 30 minutes. The pH is lto 1.1. The reaction mixture is heated at 90C for 30 minutes and is thencooled to 45C, and its pH is adjusted to pH 6.8 withapprox. 1.2 parts of50 percent strength sodium hydroxide solution. This solution containsapprox. 33 percent of the urea in the form of urones. 157.8 parts of a68.5 percent strength urea solution are introduced into this mixture,whilst stirring. The reaction solution is heated at 50C for 4 hourswhilst maintaining a pH of 6.8 to 7.0. Approx. 840 parts of thefinishing agent, with a solids content of 48 percent,'are obtained. Thefree formaldehyde content is 0.8 percent.

EXAMPLE 2 percent strength sodium hydroxide solution whilst at approx.54 percent of the urea in the form of urone. 526 parts of a 68.5 percentstrength urea solution are added at 45C. The reaction mixture is stirredfor 4- hours at 50C whilst keeping the pl-lat 7.2-7.4 by addingtriethanolamine. 2,150 parts of a 48 percent strength solution ofthe-finishing agent-according to the invention, containing 2.1 percentoffree-formaldehyde, are obtained.

EXAMPLE 3.;

1,440 parts of 2160 percent strength methylolation mixture of "urea'with formaldehyde fin the'molar ratio of 1:4, are heated to 100Candstirredwith 4 parts byvolume of 75 percent strength sulfuric acid formin utes at 100C. The reaction "mixture is then immedi- 6 'iEX'AMPIiE 5'A bleached andmerceriged can"... fabric 120 'g/m isz-padded with a;finishing liquoryvhich contains 120 parts of the product preparedaccording to Example 1 and 3 parts of ammonium chlorideper liter. Thewet pickup is 70 percent. The fabric is dried out and then thecondensation reaction is carried out for 4 mi nutes at 140C (the testresults are given in column'Aof the table). A comparison experimentiscarried outwith a fresh solution of 70 parts of crystallinedimethylolure'a and 4 parts of ammonium'chlo'ri'de, dissolved in l-literof water (column C). After 6 hours, the solutions are again applied tountreated fabric of the type described above (columns B and D). Atthisstage, the solution of the crystalline dimethylolurea isalready 'veryturbid.

RESULTS:

Untreated I fabric 1 Dimethylolurea Product according to Example Drycrease angle according to DIN 53,890

Sum of warp weft After 1 machine wash at 60C Decrease in tensilestrength in EXAMPLE 6 Unbleached rayon staple cloth (140 g/m is paddedwith a finishing liquor which contains, per liter, 200 parts of theproduct prepared according to Example 2 and 30 parts of a 30 percentstrength zinc nitrate solution. The wet pickup is 90 percent. Afterdrying the fabric, the condensation reaction is carried out for 4minutes at 140C. A comparison experiment is carried out with a freshlyprepared liquor of l 10 parts of dimethylolurea and 30 parts of a 30percent strength zinc nitrate solution per liter.

RESULTS:

Untreated fabric Product according to Example 2 Dimethylolurea Drycrease angle according to DIN 53,890 Warp weft After I wash at 60CMonsanto rating after one wash at 60C Compale AATCC Technical Manual88A-1964 T.

EXAMPLE 4 780 parts of crystalline urea are added to the reactionmixture. The reaction solution is heated at C for three hours whilstmaintaining a pH of 7.2-7.6 by means of triethanolamine. 3,950 parts ofan approx. percent strength aqueous solution are obtained.

An embossed effect produced on a ribbed calendar prior to thecondensation reaction shows similar durability to laundering in bothproducts.

We claim:

1. A process for the manufacture of a liquid finishing agent forcellulosic textiles which is stable on storage, wherein a reactionmixture obtainable by reaction or urea or methylolated urea or awater-soluble urea-formaldehyde polycondensation product withformaldehyde in an overall molar ratio of urea: formaldehyde of from 1:3to 1: 10 in aqueous solution at a pH of from 0 to 3 is adjusted to a pHof from 6 to 10 and urea is added at a temperature of from 20 for C toprovide an overall molar ratio of urea to formaldehyde of from 121.5 to1:25.

2. A process as claimed in claim 1 wherein the reaction mixture isobtained by reaction of urea or methylolated urea or a water-solubleurea-formaldehyde condensation product with formaldehyde in an overallmolar ratio of urea: formaldehyde of from 1:4 to 1:6 in aqueous solutionat a pH of from O to 3.

3. A process as claimed in claim 2 wherein the reaction mixture isobtained at a pH of from 1.5 to 2.5.

4, A process as claimed in claim 2 wherein the formaldehyde for reactionwith the urea, methylolated urea or water-soluble urea-formaldehydecondensation product is provided in the form of a polymer or acetalthereof.

5. A process as claimed in claim 2 wherein the reaction of urea,methylolated urea or water-soluble ureaformaldehyde condensation productwith formaldehyde is carried out in the presence of a mineral acid or 8strong organic acid at a temperature of from 60 to C.

6. A process as claimed in claim 1 wherein the pH of the initialreaction mixture is adjusted to from 6.4 to 9 and urea is added toprovide an overall molar ratio of urea to formaldehyde of from 1:1.7 to122.3.

7. Liquid finishing agents for cellulosic textiles when manufactured bythe process of claim 1.

8. A process for finishing cellulosic textiles wherein the textilematerial is treated with a liquid finishing agent as claimed in claim 7.

9. A process as claimed in claim 8 wherein the textile material istreated in an aqueous impregnating bath containing the liquid finishingagent and a potentially acid crosslinking catalyst.

10. Cellulosic textiles which have been finished by a process as setforth in claim 8.

1. A PROCESS FOR THE MANUFACTURE OF A LIQUID FINISHING AGENT FORCELLULOSIC TEXTILES WHICH IS STABLE ON STORAGE, WHEREIN A REACTIONMIXTURE OBTAINABLE BY REACTION OR UREA OR METHYLOLATED UREA OR AWATER-SOLUBLE UREA-FORMALDEHYDE POLYCONDENSATION PRODUCT WITHFORMALDEHYDE IN AN OVERALL MOLAR RATIO OF UREA: FORMALDEHYDE OF FROM 1:3TO 1:10 IN AQUEOUS SOLUTION AT A PH OF FROM 0 TO 3 IS ADJUSTED TO A PHOF FROM 6 TO 10 AND UREA IS ADDED AT A TEMPERATURE OF FROM 20* FOR 80*CTO PROVIDE AN OVERALL MOLAR RATIO OF UREA TO FORMALDEHYDE OF FROM 1:1.5TO 1:2.5.
 2. A process as claimed in claim 1 wherein the reactionmixture is obtained by reaction of urea or methylolated urea or awater-soluble urea-formaldehyde condensation product with formaldehydein an overall molar ratio of urea: formaldehyde of from 1:4 to 1: 6 inaqueous solution at a pH of from 0 to
 3. 3. A process as claimed inclaim 2 wherein the reaction mixture is obtained at a pH of from 1.5 to2.5.
 4. A process as claimed in claim 2 wherein the formaldehyde forreaction with the urea, methylolated urea or water-solubleurea-formaldehyde condensation product is provided in the form of apolymer or acetal thereof.
 5. A process as claimed in claim 2 whereinthe reaction of urea, methylolated urea or water-solubleurea-formaldehyde condensation product with formaldehyde is carried outin the presence of a mineral acid or strong organic acid at atemperature of from 60* to 100*C.
 6. A process as claimed in claim 1wherein the pH of the initial reaction mixture is adjusted to from 6.4to 9 and urea is added to provide an overall molar ratio of urea toformaldehyde of from 1:1.7 to 1:2.3.
 7. Liquid finishing agents forcellulosic textiles when manufactured by the process of claim
 1. 8. Aprocess for finishing cellulosic textiles wherein the textile materialis treated with a liquid finishing agent as claimed in claim
 7. 9. Aprocess as claimed in claim 8 wherein the textile material is treated inan aqueous impregnating bath containing the liquid finishing agent and apotentially acid crosslinking catalyst.
 10. Cellulosic textiles whichhave been finished by a process as set forth in claim 8.